Floyd Landis has launched a stinging attack on Team Sky, claiming the idea of marginal gains and a zero tolerance policy is a facade and “just great PR”. The former American rider who turned informant after testing positive for drugs himself scoffed at possible explanations for Chris Froome’s failed test and expects the fallout to be a death knell for Team Sky after eight years at the top.

Former US Postal Service rider Landis, who won the Tour de France in 2006 before being told of a positive test for testosterone 72 hours later, contributed to the downfall of Lance Armstrong with his testimony of widespread doping in cycling.